Zemerl - A database of Jewish songs (Hebrew, Yiddish, Ladino) including song lyrics, translations, information about the songs and other resources. - http://www.zemerl.com/
Hebrew Songs - Collection of Hebrew songs, transliterated and translated into English, with sound clips. - http://www.hebrewsongs.com/
Theory of Jewish Prayer Modes - Exposition by Josh Horowitz on the system of Jewish prayer modes, or Staygers, which forms the basis of all Jewish music. The article is written from the perspective of Klezmer music. - http://www.klezmershack.com/articles/horowitz/horowitz.klezmodes.html
Jewish Music Resources - Listing of Jewish music resources maintained by Roger Harris. - http://www.nationalfinder.com/jmr/
Jewish Music WebCenter - Comprehensive directory of Jewish music on the Internet, by a librarian of Brandeis University. - http://www.jmwc.org/